Charged-particle-beam (e.g., electron-beam) lithography apparatus have utility for producing feature sizes of 0.2 .mu.m or less on a sensitive substrate as used in, e.g., making semiconductor devices and displays. Conventionally, when forming such patterns on the sensitive substrate using a charged-particle-beam (e.g., electron-beam) lithography apparatus, pattern formation is performed using a large exposure dose of 16 .mu.c/Cm.sup.2 or higher to prevent dimensional non-uniformities resulting from electron emission shot noise.
Problems can arise when forming a pattern with such a large dose. Problems include: (1) reduced throughput; (2) heating of the substrate (e.g., wafer) by incident charged particles (e.g., electrons) causing a deterioration of registration and alignment between, e.g., adjoining projection regions; and (3) heating of the resist, making it impossible to form an accurate pattern on the substrate.